• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.2
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• pp.145-151
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• 2014

Recently, the growing demand for weight reduction and improved structure durabilityfor commercial vehicles has led to active research into the development and application of suitablecomposite materials. This studysuggests abimaterial composite frame produced by apultrusion process to replace steel frames. We focused on the development of a composite frameconsisting of two types of materialsby mixing anorthotropic material with anisotropic material. The inside layer consisted of an aluminum pipe, and the outside layer was composed of a glass fiber pipe. To determine the strength and failure mechanisms of the composite material, tensile tests, shear tests, and three-point bending tests were conducted, followed by fatigue tests. After static testing, the fatigue tests were conducted at a load frequency of 5 Hz, a stress ratio (R) of 0.1, and an endurance limit of $10^6$ for the S-N curve. The resultsshowed that the failure modes were related to both the core design and the laminating conditions.

• Tuberculosis and Respiratory Diseases
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• v.78 no.4
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• pp.428-431
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• 2015

Epithelial-myoepithelial carcinoma (EMC) of lung is a minor subset of salivary type carcinoma of lung of known low grade malignancy. Histologically, two-cell components forming duct-like structure with inner epithelial cell layer and outer myoepithelial cell layer are characteristics of EMC. In salivary gland, dedifferentiation of conventional low grade malignancy has been reported and is thought to be related with poor prognosis. However, precise histomorphology and prognostic factors of pulmonary EMC have not been clarified due to its rarity. Herein, we reported a rare case of EMC presented as endobronchial mass in a 53-year old woman, which showed predominant solid lobular growth pattern and lymph node metastases.

• Korean Journal of Plant Resources
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• v.6 no.2
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• pp.141-145
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• 1993

Apexes of basidia in Rhodophyllus(synonyum of Entoloma) muraii var. albus are divided into four sections or depressed in the center. A spore is formed by inflation of the apex of the sterigma. The apex of the sterigma is swollen and changed from a papilla through a penisform and a club into a globeform. Six spots of globose spore are regularly or irregularly depressed with hilum axes. Finally the spores are cuboid. Basidia of Entoloma squamiferrum are developed from hymenium layer of crator-shaped parabasidium. Apex of basidium is flat or depressed in the center. Although four sterigmata are developed, only two sterigmata are symmetrically swollen to two spores in certain basidia. It means that two sterigmata among four sterigmata are infertile. The apex of the sterigma is swollen into a paillaform, and then turned into a penisform. It is swollen from a clubform into a globeform. Six spots of the surfaces of globose spore are deperssed with hilum axes. Finally the spore is cuboid, and then it is released from hilum. Four sterigmata of papillaform of E. violaceobrunneum are developed from cartor-shaped basidium. The apex of sterigma is swollen to a small globeform. And then it is swollen to a clubform. The clubform is again swollen to a ellipticalform, and then more than six spots of spore surfaces are ramomly depressed with hium axes. When the depression of surface of a elliptical spore is over, it is the multi-angular spore of the heterometrical-form.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.1
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• pp.77-83
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• 2004

In this study, the spray cooling heat transfer and working characteristics of the screen wick heat pipe with ultrasonic spray cooling system in condenser were experimentally investigated. The heat pipe was made of copper tube 300 mm long with inner diameter of 11.1 mm. The evaporator and condenser lengths of heat pipe were 40, 200 mm and the wick structure consists of two layer of 100 mesh copper screen. The experimental results show that the ultrasonic spray cooling increases the heat transfer rate on the condenser surface, and the total thermal resistance of heat pipe system decreases remarkably. A comparison is made for the two working fluids, water and ethanol. The surface temperature of the ethanol tube in evaporator section becomes higher than that of the water tube. Thus, the experimental result shows that water is more useful than ethanol as the working fluid because of increasing the operational limit within this experimental conditions.

• Journal of the Korean Physical Society
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• v.73 no.11
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• pp.1663-1674
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• 2018

We propose the Poynting vector analysis of the air mode in a top-emitting organic light-emitting diode (OLED) by combining the transfer matrix method and dipole source term. The spatial profiles of the time-averaged optical power flow of the air mode are calculated inside and outside the multilayer structure of the OLED with respect to the thickness of the semi-transparent top cathode and capping layer (CPL). We elucidate how the micro-cavity effect controlled by the thickness variation of the semi-transparent top cathode or CPL affects the internal optical power and absorption loss inside the OLED multilayer and the external optical power coupled into the air. When the calculated absorption loss and external power obtained by the proposed Poynting vector and currently-used point dipole models are compared, two calculation results are identical, which demonstrates the validity of the two models.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.9 s.339
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• pp.9-18
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• 2005

To make high-performance, low-power transistors beyond the technology node of 60 nm complementary metal-oxide-semiconductor field-effect transistors(C-MOSFETs) possible, the effect of electron mobility of the thickness of strained Si grown on a relaxed SiGe/SiO2/Si was investigated from the viewpoint of mobility enhancement via two approaches. First the parameters for the inter-valley phonon scattering model were optimized. Second, theoretical calculation of the electronic states of the two-fold and four-fold valleys in the strained Si inversion layer were performed, including such characteristics as the energy band diagrams, electron populations, electron concentrations, phonon scattering rate, and phonon-limited electron mobility. The electron mobility in an silicon germanium on insulator(SGOI) n-MOSFET was observed to be about 1.5 to 1.7 times higher than that of a conventional silicon on insulator(SOI) n-MOSFET over the whole range of Si thickness in the SOI structure. This trend was good consistent with our experimental results. In Particular, it was observed that when the strained Si thickness was decreased below 10 nm, the phonon-limited electron mobility in an SGOI n-MOSFT with a Si channel thickness of less than 6 nm differed significantly from that of the conventional SOI n-MOSFET. It can be attributed this difference that some electrons in the strained SGOI n-MOSFET inversion layer tunnelled into the SiGe layer, whereas carrier confinement occurred in the conventional SOI n-MOSFET. In addition, we confirmed that in the Si thickness range of from 10 nm to 3 nm the Phonon-limited electron mobility in an SGOI n-MOSFET was governed by the inter-valley Phonon scattering rate. This result indicates that a fully depleted C-MOSFET with a channel length of less than 15 m should be fabricated on an strained Si SGOI structure in order to obtain a higher drain current.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.3
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• pp.55-60
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• 2020

The recent semiconductor packaging technology is evolving into a high-performance system-in-packaging (SIP) structure, and copper-to-copper bonding process becomes an important core technology to realize SIP. Copper-to-copper bonding process faces challenges such as copper oxidation and high temperature and high pressure process conditions. In this study, the bonding interface quality of low-temperature copper-to-copper bonding using a two-step plasma treatment was investigated through quantitative bonding strength measurements. Our two-step plasma treatment formed copper nitride layer on copper surface which enables low-temperature copper bonding. The bonding strength was evaluated by the four-point bending test method and the shear test method, and the average bonding shear strength was 30.40 MPa, showing that the copper-to-copper bonding process using a two-step plasma process had excellent bonding strength.

• Journal of the Korea Fashion and Costume Design Association
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• v.11 no.2
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• pp.33-42
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• 2009

The purpose of this study was to research the development of jacquard fabrics by the Bi-Dan patterns of Dan-Chung as one of the traditional korean symbols. For performing this design study, it designed a surface design of the geometric images in Bi-Dan patterns using by EAT Jacquard Textile CAD system and simulated to fabrics for the clothing & bags. To consider the modern image of Bi-Dan patterns in the Dan-Chung motives, the theoretical background was made on the basic elements, compositions and symbolic meanings of Dan-Chung patterns. To merchandise the fashion items and see the visual image, these jacquard fabric simulations was processed by two-dimension modeling through YoungWoo CNI CAD. The applied weave structure was based on a single layer of 5 or 10 points-satin and a double layer of 8 points-satin. Among the fabric simulations of Bi-Dan patterns, the six simulated fabrics were woven into the real jacquard fabrics under the electronic Stabuli jacquard loom in $120{\sim}130$ picks per inch and 171 ends per inch. These developed jacquard fabrics of Bi-Dan patterns were appeared a contemporary yet ethnic feeling so that they could make use of the unique korean cultural products by the further commercialization.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.6
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• pp.592-597
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• 2004

Porous silicon(PS) has received much attention as a sensitive material of chemical sensors because of its large internal surface area. In this work, we fabricated gas-sensing devices based on the porous silicon layer which could be applicable to the measurement of blood alcohol content(BAC), and estimated their electrical properties. The structure of the sensor is similar to an MIS (metal-insulator-semiconductor) diode and consists of thin Au/oxidized PS/PS/p-Si/Al, where the p-Si substrate is etched anisotropically to reduce the thickness. We measured C-V curves from two types of the samples with the PS layer treated by the different anodization current density of 60 or 100 mA/cm$^2$, in order to compare the sensitivity. As a result, the magnitude and variation of capacitances from the devices with the PS formed under the current density of 100 mA/cm$^2$ were found to be more detectable due to the larger internal surface.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2519-2521
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• 2003

In this paper, we propose Self-Organizing Fuzzy Polynomial Neural Networks(SOFPNN) architecture for optimal model identification and discuss a comprehensive design methodology supporting its development. It is shown that this network exhibits a dynamic structure as the number of its layers as well as the number of nodes in each layer of the SOFPNN are not predetermined (as this is the case in a popular topology of a multilayer perceptron). As the form of the conclusion part of the rules, especially the regression polynomial uses several types of high-order polynomials such as linear, quadratic, and modified quadratic. As the premise part of the rules, both triangular and Gaussian-like membership function are studied and the number of the premise input variables used in the rules depends on that of the inputs of its node in each layer. We introduce two kinds of SOFPNN architectures, that is, the basic and modified one with both the generic and the advanced type. The superiority and effectiveness of the proposed SOFPNN architecture is demonstrated through nonlinear function numerical example.